The largest mammal in the world is the blue whale. Adult blue whales can reach lengths of up to 100 feet and weigh as much as 200 tons or more, making them the largest animals to ever live on Earth. They primarily feed on tiny shrimp-like animals called krill, consuming up to 4 tons per day during feeding seasons. Blue whales have a distinct blue-gray coloration with lighter spots. They are found in oceans worldwide and, despite being endangered due to past whaling activities, conservation efforts have been implemented to help their populations recover.